A study was conducted to improve upon currently used test procedures for determining the Mode I, Mode II and mixed-mode delamination toughness of ceramic matrix composite materials. Test methods and specimen geometries were chosen that may be used to test unidirectional or multidirectional layups. The test methods consisted of the Mode I double cantilever beam test, the Mode II end-notched flexure test and the mixed-mode single leg bending test. Procedures for these tests were developed that could be used at room or elevated temperature and for which a compliance calibration method of data reduction could be employed. These procedures were then used to perform a study on a Nicalon/MAS-5 fiber-reinforced ceramic to determine the effects of mode ratio, temperature and layup on delamination toughness. It was concluded that the three test methods combined can be used to provide sufficient information on the variation of toughness with mode mix for most design purposes.